The Neuropsychology Core will continue to promote the goals of the Program and contribute directly to the individual projects by providing the resources for quantifying cognitive and behavioral characteristics of all subjects through brief, standardized neuropsychological testing. This will be done in conjunction with the Human Subjects/Data Analysis Core. The set of neuropsychological tasks administered by the Neuropsychology Core centers on measures of the specific domains of behavior that we found to be relevant to the proposed biomechanical studies based on data we have gathered in the first years of funding of this Program (e.g., psychomotor speed, attention, problem solving, affect/behavior). Several other brief measures have been added, based on specific needs associated with the Projects (e.g., assessments of working memory and visuospatial ability). The assessment will broaden the generalizability of the findings and allow finer analyses of these aspects of neuropsychological performance that relate to motor control. Within the overall goal of determine what are the critical neuropsychological domains that may underlie mobility impairments in the elderly and how these variables may relate to both physical capacities and psychological factors, the Neuropsychology Core will continue to be hypothesis driven. Neuropsychological tasks will be used to predict mobility task outcomes with the expectation that raising task complexity and presence of motor and/or cognitive impairments will call for increasingly higher cognitive skills to assure adequate coping and adjustment, as measured by successful task outcome. Interrelationships among neuropsychological performance domains compared between young and older subjects also will continue to be an important area of study as will the association between measures of neuropsychological ability and functional status. Finally, the Neuropsychology Core will continue to assist in the design, execution, analysis, and presentation of research with the Program as a whole.